Barrels for rifles and pistols with running lands and grooves

ABSTRACT

A barrel for rifles and pistols equipped with lands and grooves, wherein the greatest measure of the groove caliber of the barrel corresponds with the minimum measure of the diameter of the projectile, and the land caliber amounts to about 96 percent of the groove caliber.

O Umted States Patent 1 1 3,786,589 Kaltmann 1 Jan. 22, 1974 [54]BARRELS FOR RIFLES AND PISTOLS 2,293,114 8/ 1942 Carter 42/78 WITHRUNNING LANDS AND GROOVES 3,100,358 8/1963 Robinson, Jr... 42/783,562,945 2/1971 Mikola 42/78 [75] Inventor: Hans-Joachi tmann,3,643,364 2/1972 Koch 4217s Dusseldorf, Germany N F PA [73] Assignee:Rheinmetall GmbH, Dusseldorf, OREIG TENTS F APPLICATIONS Germany 3,16612/1861 Great Bntatn 42/78 [22] Filed: June 1971 PrimaryExaminer--Benjamin A. Borchelt [21] Appl. No.: 153,207 AssistantExaminer-C. T. Jordan Attorney, Agent, or Firm-Ernest G. Montague [30]Foreign Application Priority Data June 18, 1970 Germany 2029877 [57]ABSTRACT [52] us CL u 42/78 A barrel for rifles and pistols equippedwith lands and [5]] In; CL 17/10 grooves, wherein the greatest measureof the groove [58] Field of 42/78 caliber of the barrel corresponds withthe minimum measure of the diameter of the projectile, and the land I56] References Cited caliber amounts to about 96 percent of the groovecal- UNITED STATES PATENTS 1,275,028 8/1918 Holter 42/78 3 Claims, 2Drawing Figures ,IIIII Iln- I KN 1 I e 1 a Q a t *7 G 5 1 7 K "*I'IIIIPATENTEI] JAN 2 2 I974 SHEET 2 IF BARRELS FOR RIFLES AND PISTOLS WITHRUNNING LANDS AND GROOVES The present invention relates to a barrel forrifles and pistols with running lands and grooves, from whichprojectiles can be shot without a guide band.

In conventional manner the barrels of these rifles or pistols have agroove profile formed of grooves and lands, whereby during firing in thebarrel already a rota 'y movement is imparted about its longitudinalaxis to the projectile. The groove caliber takes into considerationthereby in general the tolerance of the diameter of the projectile andcorresponds mostly with its high- 'est dimension. The land caliber, thatmeans, the open distance between the lands, is thereby smaller than thediameter of the projectile. The lands serve as guide faces for theprojectile, while the twist is imparted to the projectile.

In connection with rifles and pistols, one is always desirous to improvethe outputof the rifle or pistol in relation to the most importantfactors. These are the operating life of the barrels, the firing rangeof the rifle or pistol and the target picture. All three factors aredependent, in addition upon the material of the barrel and thecharacteristic of its inner face, first of all, upon the formation ofthe caliber, that means upon the profile cross section.

A great problem is caused, for some time, in the formation of theprofile cross section. At the transfers from the landsinto the groovesremain namely small cross sectional faces which are not filled by theprojectile. At those places, parts of the powder gases can escapepassing the projectile, whereby the powder gases are not fullyexploited. The hot powder gases flowing through the narrow splits withhigh speed cause high wear of the inner wall of the barrel, whereby in acomparatively short time period, the firing range and the obtainedtarget pictures become unsatisfactory. Itihas been recognized by theexperts in the field, that in relation to the observed disadvantagesimprovements can be obtained, if one avoids sharp transfers on the landsto the grooves. By this arrangement, in the first place, a takeoff fromthe jacket face of the projectile is avoided. Furthermore, within theframe work of these recognitions, a plurality of proposals have beenmade for avoidance of these disadvantages. It has been already proposedto form the profile cross section of a rifle? harrelas a polygon withrounded edges, whereby grpoves and, lands run into each other withoutedges. In accordance with another known proposal, the lands shouldcomprise chords in a circle and the grooves should comprise sections ofthis circle.

Theknown proposals exhaust themselves, however, mostly only in generalinformation, without giving a definite lesson, 1h0W to design and todimension the grooves and lands. Thus, experiments for the realizationof these general proposals in different firearms did notonly not bringabout the desired results or only apparent results, by achieving eithera lower wear at the expense of the target picture or of the firingrange, or vice versa. This lies first of all in the fact that the setrequirements influence each other in an opposite sense and further alsoin the fact that the conventional production tolerances, which amount inrifles and pistols of this order from about 0.02 to 0.03 mm., have notbeen considered.

It is therefore one object of the present invention to provide a barrelfor rifles and pistols, which is characterized on the one hand by anincreased firing range, as well as by a good target picture and, on theother hand, by an increased operational life.

Based on the old recognitions found by experts in the field, it isanother object of the present invention, starting with a barrel equippedwith grooves and lands, wherein the highest measure of the groovecaliber corresponds with the minimum measure of the diameter of theprojectile and the land caliber amounts to about 96 percent of thegroove caliber. By such dimension of the profile cross section,appreciable improvements of the rifle or the pistol concerning thetarget image, the firing range, and the operational life are obtained.

Now, the requirements set to the rifle or pistol are different,depending upon the use of the rifle or pistol. Thus, for example, incase of a sporting gun the obtainable target picture is the mainrequirement, while in an infantry gun with increased barrel wear, thelonger life is to be considered the main requirement, with extensiveimprovement also of the other values. Within the framework of thepresent invention, it is now possible, by stronger consideration of oneor the other factor, to adjust a profile cross section of the barrel tothe intended use of the firearm.

For a gun with which in the first place an extremely good target pictureis to be obtained, one uses advantageously a barrel equipped with fourlands and grooves each, which barrel is characterized by the feature,that the grooves or lands consist in known manner of sections of acircular arc, the radius of which corresponds with the radius of theminimum diameter of the projectile and the lands comprise chords in thiscircle. Jointly with the dimensioning of the calibers in accordance withthe main feature of the present invention, such barrel is destined inthe first place for the use in connection with sporting guns.

For a gun the barrel of which should have in addition to a good targetpicture, first of all, a high operational life, one provides suitably aprofile with three grooves, to which are oppositely disposed threelands. In the use of the teaching of the present invention, the groovesand lands comprise sections of a circular arc, the radius of whichcorresponds with that of the minimum diameter of the projectile, and thelands comprise circular arcs, the radius of which is about 14-18 percentlarger than the radius of the minimum diameter of the projectile. Abarrel equipped with this profile is thus in the first place destinedfor the use of guns with increased barrel wear, that means for infantryguns.

With these and other objects in view, which will become apparent in thefollowing detailed description, the present invention, which is shown byexample only, will be clearly understood in connection with theaccompanying drawings, in which:

FIG. 1 is a profile cross section with four lands and grooves and FIG. 2is a profile cross section with three lands and grooves.

Referring now to the drawings and in particular to FIG. 1, the profilecross section disclosed in FIG. 1 has four grooves Z and lands F and inthe first place is destincd for barrels of sporting guns, in which theobtaining of a good target picture is the main requirement. In a circlewith the radius Rz, which corresponds with the radius of the minimumdiameter G of the projectile, the

lands F are disposed symmetrically, which comprise chords in thiscircle. The grooves Z are sections of this circle. The transfers fromthe lands to the lands or grooves are rounded up with the avoidance ofedges. During producing of the barrels it is to be observed, that thegreatest measure of the groove caliber corresponds with the minimummeasure G of the diameter of the projectile and the land caliber amountsto about 96 percent of the groove caliber.

The profile cross section, disclosed in FIG. 2, has three grooves Z, towhich three lands F are opposed. This profile is destined in the firstplace for guns with a great barrel wear, thus, for infantry guns. Thegrooves Z comprise sections of a circle with the radius R whichcorresponds with that of the minimum diameter of the projectile G. Theland caliber K corresponds again to about 96 percent of the groovecaliber K and the lands are formed of circular arcs, the radius R; isabout l4-l8 percent larger than the radius R of the minimum diameter ofthe projectile. Here also is to be observed, that the greatest measureof the groove caliber K corresponds with the minimum measure G of thediameter of the projectile.

The measuring rules of the invention are explained below in connection'with a calculation example for FIGS. 1 and 2, whereby FIG. 1 is to bedestined the protile for a sporting rifle or sporting pistol forcartridges of the caliber 7X64. The minimum diameter G of the projectileamounts in this projectile to 7.22 mm. This measure forms simultaneouslythe greatest measure of the groove caliber K The land caliber K, amountsto 96 percent of the groove caliber, thus 6.93 mm.

The profile in accordance with FIG. 2 is destined for an infantry gun ofNATO caliber 7.62X l.

The minimum diameter G for the projectile of this ammunition amounts to7.80 mm., which measure is simultaneously the highest measure of thegroove caliber. The land caliber K amounts to 96 percent thereof, thus7.488 mm. The radius R of the circular arc sections forming the groovesamounts thus to 3.9 mm. and the radius R of the circular arc sectionsforming the lands amounts to about 4.52 mm.

While I have disclosed several embodiments of the present invention, itis to be understood, that these embodiments are given by example onlyand not in a limiting sense.

I claim:

1. A combination of a barrel for rifles and pistols and a plurality ofprojectiles to be used therewith, comprising a plurality of projectiles,said projectiles ranging from a minimum projectile diameter to a maximumprojectile diameter,

a barrel equipped with lands and grooves, said grooves having theirlargest diameter equal to the minimum diameter of said projectile, and

the caliber of said lands being about 96 percent of the diameter of saidgrooves.

2. The barrel, as set forth in claim 1, which includes four lands andgrooves,

said grooves comprise sections of a circular arc, the radius of whichcorresponds with the radius of the minimum diameter of said projectile,and

said lands comprise chords in a circle.

3. A barrel for rifles and pistols equipped with lands and grooves,wherein thegreatest measure of the groove caliber of said barrelcorresponds with the minimum measure of the diameter of a projectile,

the land caliber amounts to about 96 percent of said groove caliber,

said grooves comprise three grooves, to which the lands are opposed,

said grooves comprise sections of a circular arc having the radius ofsaid minimum diameter of said projectile, and

said lands comprise circular arcs, the radius of which is about 14-18percent larger than the radius of said minimum diameter of saidprojectile.

1. A combination of a barrel for rifles and pistols and a plurality ofprojectiles to be used therewith, comprising a plurality of projectiles,said projectiles ranging from a minimum projectile diameter to a maximumprojectile diameter, a barrel equipped with lands and grooves, saidgrooves having their largest diameter equal to the minimum diameter ofsaid projectile, and the caliber of said lands being about 96 percent ofthe diameter of said grooves.
 2. The barrel, as set forth in claim 1,which includes four lands and grooves, said grooves comprise sections ofa circular arc, the radius of which corresponds with the radius of theminimum diameter of said projectile, and said lands comprise chords in acircle.
 3. A barrel for rifles and pistols equipped with lands andgrooves, wherein the greatest measure of the groove caliber of saidbarrel corresponds with the minimum measure of the diameter of aprojectile, the land caliber amounts to about 96 percent of said groovecaliber, said grooves comprise three grooves, to which the lands areopposed, said grooves comprise sections of a circular arc having theradius of said minimum diameter of said projectile, and said landscomprise circular arcs, the radius of which is about 14-18 percentlarger than the radius of said minimum diameter of said projectile.